Hotboxes are used saturate your ski bases with wax. By using a temperature much lower than the melting point of the ski base, hotboxes are safer for your skis than using a wax iron for base saturation. And because the heat is applied for an extended period, skis absorb more wax than can be practically done with an iron.
Why do you want your bases saturated with wax? Besides conditioning your bases to a certain hardness and water repellency, wax also protects the base from oxidizing. An oxidized base does not absorb wax well, and a base without wax tends to be slow.
As you ski, wax wears out of the base. The more saturated the bases are with wax, the longer you can ski without rewaxing to protect your bases.
Notice I said "protect" your bases, not optimize the performance of your skis. Hotboxing may saturate your bases with wax, but you may still need one or more layers of wax to tune your skis for the day's conditions (e.g.: applying high or pure fluoros or Toko Helix). If you're just training and touring, then hot boxing may be enough.
You can hotbox one layer of wax, then iron in a second, different wax and hotbox it.
Don't have or want a hotbox? For optimal ironing, I like Mark Waechter recommendations (reprinted from his Nordic UltraTune FAQ page):
For real wax absorption to occur, the base of the ski must be kept at the optimal temperature for 5+ minutes. It will continue to soak up wax for much longer. However, steadily ironing all this time can damage the base. Here is the system I have evolved:
- Crayon a protective layer of wax onto the base: this will keep the iron from coming in direct contact with the base. Then drip a little more on.
- Set your iron at the factory-recommended temperature, or about 25°C higher than the melting point of the wax. As a general rule, I rarely wax above 115°C (except for certain very rapid applications, as with Star MP100, which goes on at 135°C - but you move the iron FAST!).
- Move the iron down the entire length of the ski in one steady motion, at a speed that takes around 30-40 seconds to go from tip to tail. This avoids too much contact with one spot, thus avoiding heat build-up.
- Repeat 5 or 6 times, then put the ski aside, base up, and move to the next ski.
- When you have repeated the process with ski #2, put it aside, base up, and return to ski #1.
- Continue to alternate skis for at least three cycles.
- Allow to cool before scraping (except for very hard waxes).
Want a few more details comparing hotboxing to ironing?
Hotbox vs. Iron Shoot Out
|The optimal hotbox temperature is 50-55ºC, well below the
P-Tex melting point of 85ºC.
It's not necessary for the wax to be in a liquid state to be absorbed. Wax flows and bonds at temperatures below it's melting point.
easily crank up your iron past the point where P-Tex begins to melt, all
the way to 135ºC when P-Tex goes into full meltdown.
Irons - even good ones - also tend to spike to high temperatures.
|Deep wax impregnation||Mark Waechter of Nordic UltraTune tested wax absorption by weighing skis
before and after waxing. His findings? Hotboxed skis absorbed 2-3 times
more wax than the iron method.
Toko came up with similar results, comparing their Thermo Bag to ironing.
|Eternity - the time it take to iron as much wax into your bases as you can with a hotbox.||Hotbox|
|Speed of waxing||The longer the skis are in the box, the better: 45 minutes minimum,
3 hours best, overnight OK.
You still have to iron in a final race layer...
|5 minutes per ski, including putting the skis on to your wax bench.||Iron|
|Portability||Homemade hotboxes are heavy and bulky. Some of
us don't even have room in our home for a hotbox!
Of course, you could spend $6,000+ on a portable Toko Thermo Bag if you really wanted to...
|Throw the iron into your wax box, toss it into your car. You can use it anywhere.||Iron|
|Cost||Building a hotbox is roughly the same cost as a high-end iron. But you need an iron anyways to put the base coat of wax on your skis before you hotbox them, and again to iron in the wax of the day.||You already have an iron...||Iron|
|Key advantages||A long lasting base wax that's gentle on your bases.||A shorter lasting wax job, but faster and less expensive.|
|Key tips||Don't let the temperature of your wax box exceed 60ºC.||Keep you iron moving! The key is to melt the wax, not the base!|